Poor heating perfance after system drained and re-filled

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Poor heating perfance after system drained and re-filled

Post  PhilB on Tue Mar 08, 2011 3:32 am

Hi, I have a Boilermate 2000 and Glow-worm boiler. Recently, the boiler has overheated a couple of times which is most unusual. I backed off the bolier thermostat a touch and this prevented the cutting out.

Even more recently, a radiator has been moved which involved the system being drained and re-filled. Since re-filling and re-starting the system, the hot water has been fine but the heating just isn't getting as warm as it used too. Radiators have been fully bled.

Having observed the Boliermate ACB, I've noticed that the boiler pump doesn't seem to kick in at any point. I presume therefore that the store is relying on convected flow from the boiler.

If there is a problem with the bolier pump, would this explain the boiler over-heating? - i.e. because the host water is not being cleared quick enough from the bolier?

And would a boiler pump problem explain the reduced heating performance?...(the store temp look about normal).

If the system is drained, should the Boilermate commissioning sequence be carried out once re-filled?

Thanks in advance for any help.

Phil

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Re: Poor heating perfance after system drained and re-filled

Post  mike on Tue Mar 08, 2011 9:56 am

If the boiler pump is not working. Why?
Is there a supply to it?
If there is and the pump has failed, then that is why the boiler is over heating.
Did you bleed all the pumps?
The ACB will tell you the store temperature.
Have you the book?
If not down load one for free at Gledhill website.
Use the ACB and check the store temperature, bet it is not that hot.
Hot waster rises so the unit will be hot at the top section therefore giving hot water to the PHE.
Mike
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Poor heating perfance after system drained and re-filled

Post  PhilB on Tue Mar 08, 2011 10:22 am

Thanks for the quick reply Mike. I'll do some tests on the Boiler pump. Store temp is 69-73deg in steady state. Should it be higher than this?

Cheers

Phil

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Re: Poor heating perfance after system drained and re-filled

Post  mike on Tue Mar 08, 2011 10:44 am

Store should be at least 74c
Heating will not work unless the store is 60c or above
Boiler pump needs sorting, check if supply at pump!
And bleed pump, check if free running.
Turn off pump valves and remove pump head as the pump may appear to be working BUT the impeller could have come adrift!
Would think that when drained and the system was filled there was air in boiler pump and that will take a pump out very quick.
Although the Grundfos pumps will take some stick, but there are limits.
Mike
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Pumps seems to be ok

Post  PhilB on Wed Mar 09, 2011 5:38 am

Hi Mike, thanks again for the quick reply.

I checked out the pump and that seems to be working fine and shifting some water.

There's no power getting to the pump and the boiler pump LED is not showing, therefore I think the pump drive on the ACB is toast. Time for a new ACB I suspect, unless I can patch up the one the current ACB replaced.

When you say 'bleed the pumps' do you mean slacken the fixing nuts on either side of the pump head and let the air out?

Cheers

Phil

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Re: Poor heating perfance after system drained and re-filled

Post  mike on Wed Mar 09, 2011 7:25 am

No
On the front of the pumps is a big chrome screw.
That is where you bleed a pump and insert your finger to see if turning.
And if not to try and free up with a screwdriver etc.
You could just to try something.
Connect a lead to the boiler pump and plug that in to get some heat into the unit and to see if you have a glow worm boiler fault too.
How did you check out the pump and shifting some water?
Mike
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Sorted!

Post  PhilB on Thu Mar 10, 2011 9:47 am

Hi Mike

Connecting the boiler pump to an independent supply proved that the pump not faulty and soon got the store to a higher temperature - then the heating started to work properly.

I had a faulty ACB from a previous repair and managed to fix this by replacing the opto coupler that operates the SL to the boiler. Switched the board over and all ok now. Better than spending £250 on a new board!

Thanks a lot for the the tips and pointers.

Phil

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Re: Poor heating perfance after system drained and re-filled

Post  mike on Thu Mar 10, 2011 9:55 am

Good
Nice to sort them out!
Mike
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